1H spectroscopy has enabled the detection of numerous metabolites including glucose at 3.4 ppm during hyperglycemia. However, 1H NMR quantification of glucose in this region may be influenced by spectral overlap. Improvements in spectral resolution at high magnetic fields raised the expectation that the resolved glucose resonance at 5.23 ppm (aH1) can be measured at 4T despite its close proximity to water. The measurement of glucose at 5.23 ppm by 1H MRS offers the potential of directly quantifying glucose in the human brain without the need of 13C glucose infusions and without the danger of quantification errors due to overlap present at 3.4 ppm. Experiments were performed on a 4.0 Tesla/125cm Siemens magnet interfaced with a SISCO console using a 15 cm diameter quadrature semi-volume coil. Localization was based on STEAM (TE=20 ms, TM=10ms, TR=3s, 27 ml nominal volume). Three 25 ms Gaussian pulses were used for water suppression. Spectra were acquired in 3 min blocks, zero-filled and apodized using a mild Lorenz-Gauss filter. Three subjects gave consent as approved by the Institutional Review Board. Dextrose (20% w/v) was infused at a constant rate of 900mg/min in order to increase serum glucose from 5 mM to 20 mM in approximately one hour. The 3.44 peak was readily identified using subtraction spectra in the humans (hyper- minus eu-glycemic states). The solution and the in vivo spectrum showed maximum signal at 3.44 ppm and clear identification of the aH1 peak by resonance position and relative amplitude. In vivo observations of the 5.23 ppm signal were consistent with a concomitant increase at 3.44ppm indicating that this peak is readily observable at 4T. Therefore, direct 1H quantification of the glucose signal appears possible at 4 T. This is supported by comparing this peak relative to 10mM Cr, which gave a glucose content of 3-4 mM (plasma ~15mM), consistent with previous quantification.